“All of the capital letter acronyms we’re talking about here refer to types of memory. Memory is used to hold stuff on your devices. Phone numbers, pictures, programs, music files, they all need memory to work. Ignoring old technology no one uses anymore and exotic technology that hasn’t been released to the mass market yet, there are two types of memory: RAM and ROM. They’re similar in that they both hold stuff. Their main differences involve speed and power..”.